Bulk vendors are widely used for vending a wide variety of merchandise, from confectioneries to toys. Part of the appeal of bulk vendors is that they attract very little overhead in terms of both space and labour. Bulk vendors are typically located in high-traffic public areas, and require only periodic servicing to collect deposited coins, refill the product storage bin and, occasionally, to repair or replace parts. As such they are ideal for "self-service" sales of small articles.
For the same reasons, however, bulk vendors are frequently subject to abuse, and particularly to attempts to defeat the coin mechanism and obtain free merchandise. Many safety features have been developed over the years to prevent the theft of merchandise from bulk vendors, and while these measures have been largely successful they have only been employed in coin mechanisms which accept one coin for each turn of the handle.
Inflation has given rise to the need for bulk vendors which dispense merchandise only when two coins have been deposited into the vendor. Since conventional bulk vendors dispense merchandise with each rotation of the handle, in order to create a coin mechanism which can also be retrofitted to existing vendors it is necessary to design the coin mechanism to accept both coins before the handle can be rotated so that vendor will dispense merchandise.
This presents a difficult problem in a conventional vendor. The amount of "play" in the mechanism, i.e. the extent to which the handle can be turned without the correct coin being deposited, must be minimal in order to avoid exposing merchandise to the entrance of the dispensing chute without the proper coin being deposited (commonly known as "milking" the vendor). Thus, the coin must be measured for proper size as close as possible to the beginning of the turning cycle. In this way, if the coin is not the correct size the handle cannot be turned enough to expose merchandise to the dispensing chute, and the coin will be rejected (if too small) or must be removed from the coin slot in the carrier wheel.
In a coin mechanism which accepts two coins, this problem is exacerbated because both coins must be measured at the beginning of the turning cycle, in order to avoid both too much play in the mechanism and the dispensing of merchandise with only a single coin. However, because of size constraints, particularly if the coin mechanism is to fit into existing vendors, there is insufficient space to include two complete sets of coin measuring means.
Moreover, one of the two coins (the second in terms of the direction of rotation of the mechanism) must at some point during the turning cycle pass the coin slot for the first coin. If the second coin can be removed from the first coin slot as it passes, either without arresting the turning cycle or jamming the mechanism in the process, this also results in loss of revenue to the operator.
The present invention overcomes these disadvantages by providing a coin mechanism adapted to accept two coins simultaneously. Both coins are measured at beginning of the turning cycle, to minimize the amount of play in the mechanism and prevent milking of the vendor, by opposed measuring detents which cooperate with a single notched wheel. The notched wheel is provided with notches formed into the wheel in layers, i.e. one in each axial half-section of the wheel, and the detents are correspondingly mounted on the cover plate to cooperate only with the notches in one of the layers. In this fashion the notched wheel readily fits within the size constraints of the mechanism, and the detents are small enough and can be mounted far enough apart that they do not interfere with one another.
The invention further provides a stop member which is actuated by a cam to block access to the first coin slot as the second coin passes by it during the turning cycle, to prevent removal of the second coin. This also enables the two coin slots to be relatively far apart, which facilitates the positioning of the measuring detents, without delaying the measuring of the second coin to allow undue play in the mechanism.
These and other objects and advantages of the invention will be apparent from the description of the preferred embodiment of the invention which follows.